The most reliable, linkable resource is . This site scrapes official NVD (National Vulnerability Database) data and filters by version.
: When PHP instantiates or destroys these objects, it triggers "magic methods" (like __wakeup() or __destruct() ), allowing attackers to execute arbitrary code on the underlying server. 2. Heap-Based Buffer Overflows
Flaws in memory management and error handling within older PHP versions can inadvertently leak sensitive system data. php version 5640 vulnerabilities link
: Because official support ended in December 2018, no new CVEs are officially "fixed" by the PHP team for this version. This makes the version "low hanging fruit" for attackers who look for sites still running this legacy code.
There is no permanent security fix for PHP 5.6.40 other than upgrading. The most reliable, linkable resource is
You can find more information on these vulnerabilities and their fixes on the official PHP website:
Released on January 10, 2019, PHP 5.6.40 marked the absolute end-of-life (EOL) for the entire PHP 5 release branch. Because the PHP community stopped issuing security patches for this version years ago, legacy web applications remaining on this release remain fully exposed to automated botnets, data breaches, and ransomware. This makes the version "low hanging fruit" for
PHP 5.6.40 relies heavily on older implementations of OpenSSL (typically OpenSSL 1.0.1 or early 1.0.2 branches depending on the OS compilation).
Securing Legacy Systems: A Deep Dive into PHP 5.6.40 Vulnerabilities
Running any version of PHP 5.6 today is a significant security risk, as it no longer receives active support or regular security patches for newly discovered vulnerabilities.
Some Linux distributions and enterprise vendors backport security fixes to older PHP versions long after the official EOL date.